Housing and Method for Producing a Housing

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 from German Patent Application No. 10 2024 118 515.5, filed Jul. 1, 2024, the entire disclosure of which is herein expressly incorporated by reference.

BACKGROUND AND SUMMARY

The present invention relates to a housing and a method for producing a housing and, in particular, to a snap-fit lid design aimed at reducing failure due to dimensional changes caused by hygroscopic polymers.

In conventional housings, lids are mounted onto modules using screws or by means of snap hooks on a base component of the housing. The snap hook in this case is typically directed inwardly to allow for easy opening and closing of the housing. For example, the snap hook can be readily bent outwards and released from the snap fit.

This customary design presents several problems. Firstly, the manufacture of the lid is complex. Lids are often produced by injection moulding or casting processes. The inwardly directed snap hooks require inwardly movable protrusions (sliders) in the moulding tool, so that the lid can be removed from the tool after production. Due to safety-critical features, the lids are therefore difficult to manufacture and difficult to inspect. Another disadvantage of these conventional housings is that the lids often comprise hygroscopic polymers, which have the disadvantage that they can undergo dimensional (expansion) changes to a not insignificant extent. Expansion of these materials (e.g. due to moisture) can lead to the snap connection coming undone, as the snap hooks shift toward the release position. This repeatedly results in leakages in automotive applications, which is unacceptable in many components.

There is therefore a need for alternative housings that ensure a secure snap connection for lids even when they expand.

At least some of the afore-mentioned problems are addressed by a housing and by a method for producing such a housing in accordance with the independent claims. The dependent claims define further advantageous embodiments of the subject matter of the independent claims.

The present invention relates to a housing comprising a base component made of a non-deformable material and a lid component. The base component comprises one or more fastening openings and the lid component comprises one or more latching elements. The latching elements are engageable in the fastening openings, in order to securely close the base component with the lid component. The latching elements form tabs that point away from the housing once closed.

In the context of the present disclosure, it is primarily assumed that there are multiple fastening openings and multiple latching elements. However, exemplary embodiments should not be limited to this. Hence, for example, it is sufficient for closing the housing if only one fastening opening and one latching element with a tab formed thereon are provided. On an opposite side of the housing, a hinge or a similar rotatable support can then be provided, for example, so that a secure and reliable closure of the housing is also possible in that case. However, it is advantageous to provide fastening openings and associated latching elements on various sides, for example on all sides. A corresponding tab can then be formed on each latching element.

Optionally, the lid component comprises a material made of hygroscopic polymers. The base component may be made of a cast material (e.g. cast iron or cast aluminium) or a milled material. Examples of hygroscopic polymers include polyamides (PA) such as PA6 (polycaprolactam), PA6X (various x-values) and PPA (polyphthalamide).

Optionally, the tabs of the latching elements are each formed monolithically as a wedge, wherein the sloped portion of the wedge can be formed on the side facing away from the housing. The tabs may, for example, have a continuously increasing thickness in the direction towards an outer wall of the base component and are therefore not formed as spring tongues. The thickness of the tabs therefore changes continuously in an insertion direction (latching direction) into the fastening openings.

In particular, the rear surface of the tabs may optionally be flush with an outer wall of the base component. As a result, the tabs are supported by the outer surface of the base component when engaged in the fastening openings (they cannot flex inwards). In particular, no cavities need to be present between the rear side of the tabs and the outer wall of the base component. This has the technical effect that the tabs can latch in place without spring action and a non-destructive release after assembly is no longer readily possible. During latching, deformation (compression) of the tabs may naturally occur, wherein the deformation relaxes again after the latching process.

Optionally, the base component comprises one or more wedge-shaped projections on an outer wall of the base component behind the fastening openings in the latching direction. The wedge-shaped projections may be designed to push the tabs away from the outer wall of the base component. This offers the advantage that the latching effect is enhanced and subsequent non-destructive release is virtually impossible, as the wedge-shaped projections apply a preload to the tabs.

Optionally, the housing further comprises a sealing element made of an elastic material (e.g. a rubber ring) to provide a sealed closure of the base component by the lid component. The latching elements may engage in the fastening openings only when the sealing element is deformed. The seal therefore acts as a spring. This involves a constraint in terms of the vertical extent of the lid component and/or the distance of the fastening openings from an edge of the base component that is closed off by the lid. The seal may be formed at the edge of the base component or on an inner surface of the lid component.

Exemplary embodiments also relate to a vehicle component comprising a previously described housing. The vehicle component may comprise, or be, at least one of the following: an electro-pneumatic modulator, an electronic component, a control unit, an electronic power steering system, an electronic clutch actuator, a trailer control module, a foot brake module, a pressure control valve.

Exemplary embodiments also relate to a commercial vehicle, in particular to a truck or a bus, comprising a vehicle component as previously described.

Exemplary embodiments further relate to a method for producing the previously described housing. The method may comprise the following steps:

• • forming a base component from a non-deformable material having fastening openings;
  • forming a lid component to close the base component in a sealing manner, wherein the lid component comprises latching elements with tabs that point away from the housing following closure.

It is understood that all previously described features of the housing can be implemented through additional optional method steps. It is also understood that the sequence in which the steps are listed does not necessarily correspond to the sequence in which the process steps must be performed. The steps may also be carried out in a different order. Also, only some of the steps may be required.

Exemplary embodiments therefore overcome the problems of conventional housings using snap hooks (latching or snap-in elements) that are oriented outwards when viewed from the interior of the housing, i.e. the projections (tabs) point away from the housing and engage in loops (fastening openings) of the housing base part (base component). The result of this is that an expansion of the lid (lid component) can no longer lead to a disengagement of the snap connection, since the expansion actually enhances, rather than weakens, the snap-in effect. A further advantage is that with this arrangement, expensive sliders in the injection mould for the lid can be avoided, as the orientation of the tabs permits demoulding in a production-friendly manner. For example, the production mould can simply be pulled apart, which is not possible with the conventional, opposite orientation of the latching elements. Finally, exemplary embodiments have the advantage that tabs which, after latching, terminate flush with the rear side of the base component, prevent or hinder subsequent non-destructive disassembly of the lid. This makes it possible to detect any (unauthorized) opening of the housing.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B: show a housing according to an exemplary embodiment of the present invention.

FIG. 2: illustrates further details of the housing in accordance with additional exemplary embodiments.

FIG. 3: shows a schematic representation of a flow diagram for a method of producing the housing.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1A shows an exemplary embodiment of a housing comprising a base component 100 made of a non-deformable material and a lid component 200 that encloses an interior space 150 of the housing. The base component 100 comprises fastening openings 110 and the lid component 200 comprises corresponding latching elements 210. The latching elements 210 each have a tab 215 that is engageable with the fastening openings 110, in order to securely close the base component 100 with the lid component 200. The tabs 215 are formed in such a manner that they point away from the interior space 150 of the housing once the housing is closed.

According to exemplary embodiments, the tabs 215 of the latching elements 210 are monolithically formed as wedges. A thickness D of the tabs 215, measured in a direction perpendicular to a side wall 160, varies monotonically in the insertion direction R of the latching elements 210 into the fastening openings 110 of the base component 100. Furthermore, since a rear surface 216 of the tabs 215 terminates flush with an outer wall 160 of the base component 100, the tabs 215 are supported by the outer surface 160 during engagement in the fastening openings 110. As a result, they can no longer be pressed back. Insertion of the latching elements 210 into the fastening openings 110 may therefore occur through deformation of the tabs 215, but not via a spring effect such as a tilting of tongue-like projections, for example. The latter would have the disadvantage that the housing can easily be reopened, which the exemplary embodiments aim to prevent.

FIG. 1B shows the same housing along the cross-sectional line B-B′ in FIG. 1A, so that the interior space 150 is centrally positioned and laterally enclosed by the base component 100.

Although exemplary embodiments also relate to cases in which only one latching element 210 engages in a single fastening opening 110 (with a hinge potentially present on the opposite side), it is advantageous to provide one or more latching elements 210 with corresponding fastening openings 110 on various sides of the housing. According to the illustrated exemplary embodiment, two latching elements 210 and two associated fastening openings 110 may be provided on each of the long sides of the rectangular housing, and one latching element 210 with a corresponding fastening opening 110 may be provided on each of the short sides of the housing. This ensures that all sides of the housing are securely fastened.

Even though in the illustrated exemplary embodiment the fastening openings 110 are formed in a continuous shoulder region surrounding the outer wall 160 of the base component 100, according to further exemplary embodiments, the fastening openings 110 may be formed in tabs or loops. Likewise, the latching elements 210, as well as the fastening openings 110, may take on any arbitrary shapes. The rectangular cross section shown (perpendicular to the insertion direction R) offers the advantage of ensuring reliable latching, even when the lid component 200 expands significantly due to moisture.

According to exemplary embodiments, the lid component 200 may be made of a material comprising hygroscopic polymers. In particular, a polyamide (PA, PA6, PA6X, PPA) may therefore be used as the material for the lid component 200. The base component 100 may be composed of a cast material (e.g. iron or aluminium) or a milled material.

When exposed to moisture, the base component 100 will therefore undergo little to no change. However, the lid component 200 will expand due to moisture (hygroscopic effect). However, because the tabs 215 extend away from the outer wall 160 of the base component 100, an expansion of the lid component 200 leads to a reinforcement of the latching effect, rather than a release of the latching engagement of the lid component 200. A release of the latching engagement by the latching elements 110 (snap hooks) due to changes in size (dimensional changes) which may occur through water absorption by the lid component 200, for example, is therefore ruled out.

FIG. 2 illustrates further optional details of the housing in accordance with additional exemplary embodiments.

According to the exemplary embodiment shown, the base component 100 comprises one or more wedge-shaped projections 120 on the outer wall 160 of the base component 100 located in the insertion direction R behind the fastening openings 110. The wedge-shaped projections 120 press the tabs 215 away from the outer wall 160 of the base component 100, thereby reinforcing the snap-in effect. This offers the advantage that, once latched, bending the tab 215 back towards the outer wall 160 is virtually impossible. The wedge-shaped projections 120 apply a preload to the latching elements 210 (after engagement), so that the latching connection is reliably protected.

According to the exemplary embodiment shown, the housing further comprises at least one sealing element 300 made of an elastic material (e.g. a rubber ring), which is arranged between the base component 100 and the lid component 200 to provide a sealed closure of the housing. The sealing element 300 may, for example, be formed in a groove 130 located in a peripheral region of the base component 100. However, the sealing element 300 may also be formed in an interior region of the lid component 200, where it makes contact with the edge region of the base component 100.

The dimensions may be selected in such a manner that, after the latching elements 210 engage in the fastening openings 110, the sealing element 300 is deformed, thereby ensuring a reliable seal.

FIG. 3 shows a schematic representation of a flow diagram for a method for producing the housing. The method comprises the steps:

• • forming S110 a base component 100 from a non-deformable material with fastening openings 110;
  • forming S120 a lid component 200 to close the base component 100 in a sealing manner, wherein the lid component 200 comprises latching elements 210 with tabs 215 that point away from the housing once closed.

Exemplary embodiments are particularly applicable to housings with base components 100 made of a cast material (e.g. cast iron, cast aluminium or similar), while the lid component 200 may comprise any material. However, exemplary embodiments are particularly advantageously applicable to the use of hygroscopic polymers for the lid component 100, such as PA6, PA66 or PPA, for example, which can be used in combination with a cast material for the base component 100. The orientation of the latching elements 210 ensures a reliable snap connection in this case.

Exemplary embodiments can be used in a wide variety of applications, for example for an electropneumatic modulator, control units, electronic power steering systems, electronic clutch actuators, trailer control modules, foot brake modules and pressure control valves.

Another advantage of exemplary embodiments lies in the field of security. It is often necessary to prevent, or at least detect, unauthorized opening of housings, in order to avoid tampering with safety-critical electronics or other safety-related components. The exemplary embodiments are particularly suitable for such housings, since once closed, the housing can only be opened by destruction. Nevertheless, the housing can be closed quickly and easily by simply snapping it together. The exemplary embodiments achieve this through latching elements with monolithically formed tabs that can no longer be readily removed from the fastening openings 110, since the latching elements 210 abut directly with their rear surfaces 216 against an outer wall 160 of the base component 100. Bending back the latching elements 210 to remove the tabs 215 from the fastening openings 110 is therefore impossible.

Further advantages relate to the cost-effective manufacture of the lid component 100 and the base component 200, which are particularly suitable for the combination of hygroscopic materials with cast materials. Even if the lid component 200 absorbs water to a certain extent and thereby increases in size, the connection between the base component 100 and the lid component 200 remains reliably secured despite the increase in size. The outward-facing latching is in fact reinforced rather than compromised by the growth in size of the lid component 200.

In addition, manufacturing tolerances for the lid component 100 can be relaxed, which would otherwise make production of the lid component 100 more difficult. Another fundamental advantage lies in cost reduction, achieved through the elimination of sliders or other movable protrusions in the manufacturing process. Instead, by cleverly designing the elements in the direction of a general tool opening, such elements can be entirely dispensed with.

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.

LIST OF REFERENCE SIGNS

• • 100 base component
  • 110 fastening opening(s)
  • 120 wedge-shaped projection
  • 130 peripheral groove at the edge of the base element
  • 150 housing interior
  • 160 outer wall of the base component
  • 200 lid component
  • 210 latching element(s)
  • 215 tab(s)
  • 216 rear surface of the tab
  • 300 sealing element
  • D thickness of the tab(s)
  • R insertion direction, latching direction